These additional Ticker refactor changes include:
- Separate update() from requesting an animation frame
    - This allows calling update() with a completely separate animation/ticking API if necessary or one chooses
- Complete all TODOs
    - Added const.TARGET_FPMS
    - Added readonly property ticker.FPS
    - Added readwrite property ticker.minFPS
- added polyfilled "performance" to jshint globals
    - removed `global` in usages of it